Landing: 6e3bda5937ea
Project / Subsystem
gcc / target/i386
Date
2026-07-16
Author
Richard Biener
Commit
6e3bda5937eab9120635e5ddf15c7e332db69583
Source
github
Perf win
Yes
Breaking
No
All attributes
- project
- gcc
- subsystem
- target/i386
- patch_id
- —
- commit_hash
- 6e3bda5937eab9120635e5ddf15c7e332db69583
- source_type
- github
- headline
- i386 reduction expansion honors preferred horizontal add
- tldr
- The i386 backend now better respects the `v2df_reduction_prefer_haddpd` option for vector reductions.
- author
- Richard Biener
- outcome
- committed
- performance_win
- true
- breaking_change
- false
- series_id
- —
- series_parts
- []
- tags
-
- • x86
- • optimization
- • vector
- discussion_id_link
- —
- bugzilla_pr
- —
- date
- 2026-07-16T00:00:00.000Z
The i386 backend’s ix86_expand_reduc function now correctly honors the TARGET_V2DF_REDUCTION_PREFER_HADDPD option. This ensures that when this option is enabled, the expansion of reduc_plus_scal_V2DF operations prioritizes using the haddpd (horizontal packed double-precision add) instruction for better performance. A test case in gcc.target/i386/pr54400.c covers this functionality.